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1978 Oldsmobile Cutlass Supreme Daily Driver LQ4 Swap

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  • 1978 Oldsmobile Cutlass Supreme Daily Driver LQ4 Swap

    Figured I would go ahead and start a thread on the new car. It's a 1978 Oldsmobile Cutlass Supreme that is in surprisingly good shape. I'm almost tempted to just fix a few minor issues with the car and drive it as is, but the point of this exercise was to find a car to install my turbo-ready LQ4 engine in and drive it as my one and only daily vehicle. I searched for cars in the price range equal to the value of the '66 T-bird I was selling and the back-half kit I also had up on Craigslist. That was $1500, and it returned a host of mid-80s Camaros and mid to late 70s large 4-door cars. One thing behind this project is the need for a mid-sized car that I can comfortably put two kids in the back seat or haul my dog and I to and from school (4 hour trip) each day. Camaros have proved impracticable for this task and the full-size cars are way too much extra steel to drag around on frequent long trips. However, a 1979 Malibu popped up one day and I was intrigued. I had never considered G-body cars before, although I appreciated the Monte Carlo SS and Grand National, they were either out of my price range, or in too bad of shape to be a worthy beginning to my project. This had to be a running, driving car to begin with, but I was on to something. Turns out, the 1978-91ish G-bodies aren't very popular due to their battering ram bumpers, therefore they sit for sale for long periods of time and are priced lower than later cars in worse shape. It only took a few days and I found it:





    1978 Oldsmobile Cutlass Supreme, Olds 350/350, Runs, drives, all electrical works, t-tops (they don't leak!), body is straight but needs paint, interior is CLEAN and complete minus headliner, suspension, wheels, tires and brakes all good. The guy wanted $1500.

    I sold the T-bird and back-half kit and had $1200 in my pocket, my buddy picked me up and we went down to see it. After crawling all over it and taking it for a drive I was surprised at how good of condition it was actually in. I came back and offered the guy $1,000 "cash" (it's always cash, but it's fun to say that when negotiating). He balked at that and said $1,400. I told him I could do $1,200 but not a penny more. Turns out he had a dental bill to pay and reluctantly agreed to sell it to me at that price.

    On the drive home this is what I discovered about the car: it is very, very comfortable and rides well. Needs a minor adjustment to the alignment. The car is SLOW. Engine doesn't make much power and the rear gear is terrible. Should be 2.73 or 2.97, but I wouldn't be surprised if a 2.30 gear snuck in there at one point. I'm going to have to figure that out, because I can live with 2.97 gears for a while, but 2.30 would not work with the build plan...and the budget doesn't appear to have money for a gear swap. Also, the kick-down cable is disconnected and the trans likes to shift into 3rd ASAP and stay there. Makes driving a bit of an exercise at times. I slapped some new wiper blades on the car ($22), replaced the accessory belts ($10) because the previous belts were WAY too big and proved to be ineffective. The state took $147 of my hard earned money for the privilege of purchasing a car and transferring the title.

    Total Build Cost: $1379
    Last edited by 1970camaroRS; October 23, 2013, 12:23 PM.
    1970 Camaro RS - SOLD | 2000 Camaro SS - Traded in for a Hyundai...
    1966 Ford Thunderbird - SOLD | 1963 MGB, abandoned V8 project, FOR SALE/SCRAP

    1978 Cutlass - Post Lay-off daily driver

  • #2
    Drivetrain Options and Plans

    From day 1 the plan was to find a car I could quickly and easily install my 6.0L LQ4 in that also fit the other criteria I needed. I think I found the car, so I started putting together a budget and plan of action. After pricing headers or a fuel system to support a small turbo, I started thinking about selling the LQ4 and finding a 455 and a 200r4. This would be a quick, easy and fairly cheap way to cure the Olds 350's lack of power, but would sacrifice the fuel mileage I would enjoy if I stayed with a fuel injection system. I thought for a while of doing a carb swap on the LQ4 again, but decided against it for the same reasons.

    I had one deal in the works for a trade of my LQ4 for a 455 and 200r4, and almost had another deal to sell the LQ4. Then luck stuck and a friend local to me had a 4L80E 4 speed auto that is in "might be good" condition for next to nothing. It's also the correct era to be completely compatible with the LQ4 and a factory harness and computer. I plunked down $250 and hauled the transmission back in the trunk of the Cutlass. Yep, the project car is also the parts hauler.

    So, now the plan is this:

    LQ4 6.0L engine, headstuds, rodbolts, stock heads, truck intake, truck exhaust manifolds, mild Howard's cam (226 @.050, .570 lift), truck alt and power-steering. I already have the mount adapters, flywheel, starter, and a few other related bits.

    4L80E - I will just clean it, paint and install. Nothing more. Will need a 2,500 or 3,000rpm stall converter to work with the cam and terrible rear gears. It's not cheap. Will also need an electric speedo or cable-x box. I like electric speedos. An aftermarket shift will also be used, likely something from B&M. Special note: the 4L80E will require a different transmission cross-member. Good news is that these aren't terribly expensive.

    Fuel system, harness and computer - most likely will buy it from PSI Conversion instead of doing it myself from a junkyard because I need it to work with the least amount of fuss. It adds to the cost, but it should help make this swap painless and simple. Everything else will be sourced from junkyards or rockauto.

    The car itself- needs to be one color. I will just spray it black in my driveway. Also needs different bucket seats because the ones in my car right now aren't correct for a 2-door and won't tilt forward. Also needs a headliner. Car came with new weatherstrip, so I will install that after I paint the car.

    I do have a small problem with this being a $5,000 challenge car. I don't know the value of my LQ4 with its modifications. The engine was a $1,000 value trade made years ago. The studs, bolts, cam, valvetrain is all about $1,000 more. So, I'm calling it $2,000. Plus $250 for the trans.

    New Total Build Cost - $3629

    Don't think I'm making it under $5,000, but I will try.
    Last edited by 1970camaroRS; October 23, 2013, 01:08 PM.
    1970 Camaro RS - SOLD | 2000 Camaro SS - Traded in for a Hyundai...
    1966 Ford Thunderbird - SOLD | 1963 MGB, abandoned V8 project, FOR SALE/SCRAP

    1978 Cutlass - Post Lay-off daily driver

    Comment


    • #3
      Looks like a good plan, I hope you can make it to the end!

      Comment


      • #4
        Love the car and the project. When painting the car I would loose the top and the wing.

        $5k is a good goal, but total budget needs to fit you $$ and your goals
        Last edited by Russell; October 25, 2013, 11:10 AM.
        http://www.bangshift.com/forum/forum...-consolidation
        1.54, 7.31 @ 94.14, 11.43 @ 118.95

        PB 60' 1.49
        ​​​​​​

        Comment


        • #5
          I missed the under hood pic - that's pretty dang clean!
          Flying south, with a flock of bird dogs.

          Comment


          • #6
            You're doing almost the exact same thing I'm looking at. I've been trying to find a clean G-Body just for a $5k build car.

            As for the Olds 350, they're actually very sweet little motors. They make good power pretty cheap, but they need a few touches. Get it out for sale and they usually go quick. This was a favorite swap when I was in high school, Regals with Olds 350s.

            Comment


            • #7
              Originally posted by Beagle View Post
              I missed the under hood pic - that's pretty dang clean!
              Yeah, and the interior is just as clean!

              Currently in negotiations to pick up a 8.5" posi rear with 3.42 gears out of a turbo Regal/GN. It's going to kill the budget, but in the long run it should pay off.
              1970 Camaro RS - SOLD | 2000 Camaro SS - Traded in for a Hyundai...
              1966 Ford Thunderbird - SOLD | 1963 MGB, abandoned V8 project, FOR SALE/SCRAP

              1978 Cutlass - Post Lay-off daily driver

              Comment


              • #8
                Originally posted by Nophix View Post
                You're doing almost the exact same thing I'm looking at. I've been trying to find a clean G-Body just for a $5k build car.

                As for the Olds 350, they're actually very sweet little motors. They make good power pretty cheap, but they need a few touches. Get it out for sale and they usually go quick. This was a favorite swap when I was in high school, Regals with Olds 350s.
                I hope the Olds 350 sells quickly. It's a good runner and the TH350 works well too. Think I could maybe get $500 out of it? I have no idea where to price the Olds 350/TH350 combo.
                1970 Camaro RS - SOLD | 2000 Camaro SS - Traded in for a Hyundai...
                1966 Ford Thunderbird - SOLD | 1963 MGB, abandoned V8 project, FOR SALE/SCRAP

                1978 Cutlass - Post Lay-off daily driver

                Comment


                • #9
                  Originally posted by 1970camaroRS View Post
                  Yeah, and the interior is just as clean!

                  Currently in negotiations to pick up a 8.5" posi rear with 3.42 gears out of a turbo Regal/GN. It's going to kill the budget, but in the long run it should pay off.
                  I can't imagine why you wouldn't go pull an exploder 8.8 from U Pull it - $100 and $50 in bits from Currie Gear and you're dialed
                  Doing it all wrong since 1966

                  Comment


                  • #10
                    Originally posted by SuperBuickGuy View Post
                    I can't imagine why you wouldn't go pull an exploder 8.8 from U Pull it - $100 and $50 in bits from Currie Gear and you're dialed
                    It's fresh, the correct gear for my needs, no messing with brakes - it's a direct fit, the brackets are all correct and factory, the axle lug pattern matches the wheels I already have. It's 100% unbolt the old, bolt on the new, bleed the brakes and done.
                    1970 Camaro RS - SOLD | 2000 Camaro SS - Traded in for a Hyundai...
                    1966 Ford Thunderbird - SOLD | 1963 MGB, abandoned V8 project, FOR SALE/SCRAP

                    1978 Cutlass - Post Lay-off daily driver

                    Comment


                    • #11
                      Also, just picked up the front accessories I need. Alternator, powersteering pump, bracket, etc. $140.

                      New Total Build Cost - $3769
                      1970 Camaro RS - SOLD | 2000 Camaro SS - Traded in for a Hyundai...
                      1966 Ford Thunderbird - SOLD | 1963 MGB, abandoned V8 project, FOR SALE/SCRAP

                      1978 Cutlass - Post Lay-off daily driver

                      Comment


                      • #12
                        I ordered the fuel system today. Got a repop gas tank for a '87 Grand National, assorted AN fittings and adapters to work with the stock GM fuel rails, a filter, -8AN hose for supply and a -6AN for return, and a Racetronix sending unit with a Walbro 255 pump and AN fittings on the return and supply hard lines. And a solid motor mount frame pad for a SBC in a G-body. That with my poly clamshells and adapter plates should get the engine into the car. Still need a crossmember and torque converter to get going.

                        Total cost tonight was $495+$238= $733
                        New project total= $4502

                        Torque converter alone is going to bust me...still need a shifter, speedo, wire harness and computer after that!

                        On a more budget oriented note, I'm probably picking up a pair of seats this weekend for $50. The ones in the car currently don't fold forward because they likely came out of a 4 door car. Now if I could just get someone to buy the extra transmission and my MGB...
                        1970 Camaro RS - SOLD | 2000 Camaro SS - Traded in for a Hyundai...
                        1966 Ford Thunderbird - SOLD | 1963 MGB, abandoned V8 project, FOR SALE/SCRAP

                        1978 Cutlass - Post Lay-off daily driver

                        Comment


                        • #13
                          Broke the budget yesterday. Ordered a brand new custom 3,000 rpm torque converter from Circle D. All things considered, $500 plus shipping was fair. Located all the missing bolts, fittings and lines for the stock fuel rails for the intake for $30. Also picked up a Ford Econoline power steering pump pulley. This is used when installing LS truck motors into G-body cars to clear the steering box. That was $20. So another $550 into the pile.

                          Project total - $5552. Busted the budget and I still have another $1,000 or so to go for harness, computer, shifter, speedo and misc parts...plus exhaust...oh yeah, exhaust.
                          1970 Camaro RS - SOLD | 2000 Camaro SS - Traded in for a Hyundai...
                          1966 Ford Thunderbird - SOLD | 1963 MGB, abandoned V8 project, FOR SALE/SCRAP

                          1978 Cutlass - Post Lay-off daily driver

                          Comment


                          • #14
                            Originally posted by 1970camaroRS View Post
                            Broke the budget yesterday. Ordered a brand new custom 3,000 rpm torque converter from Circle D. All things considered, $500 plus shipping was fair. Located all the missing bolts, fittings and lines for the stock fuel rails for the intake for $30. Also picked up a Ford Econoline power steering pump pulley. This is used when installing LS truck motors into G-body cars to clear the steering box. That was $20. So another $550 into the pile.

                            Project total - $5552. Busted the budget and I still have another $1,000 or so to go for harness, computer, shifter, speedo and misc parts...plus exhaust...oh yeah, exhaust.
                            don't forget about this guy Wayne Hartwig ([email protected]) when it comes time for a harness....
                            Doing it all wrong since 1966

                            Comment


                            • #15
                              Originally posted by SuperBuickGuy View Post
                              don't forget about this guy Wayne Hartwig ([email protected]) when it comes time for a harness....
                              Just looked at his offerings. That is an interesting option if I can come across a vortec harness and computer on the cheap. Might still end up with a PSI harness and computer.

                              On another note, research has shown that the stock truck injectors are marginal with even a mild cam. The 8.1 Chevy injectors are a direct replacement, same height and plug style, but they are 36 lb/hr vs the stockers 24.7. While looking for a cheap source, I stumbled across a set of 8, used, from a supplier on RockAuto for $27 shipped! And a warranty. Think it's a price typo, but I jumped on it and the transaction went through and injectors shipped out. So, I guess we will see.

                              Cost - $5579
                              1970 Camaro RS - SOLD | 2000 Camaro SS - Traded in for a Hyundai...
                              1966 Ford Thunderbird - SOLD | 1963 MGB, abandoned V8 project, FOR SALE/SCRAP

                              1978 Cutlass - Post Lay-off daily driver

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